SURFACE CONTROLLED SUBSURFACE SAFETY VALVE
A safety valve for subsurface disposal equipped with an interfacing element of elastomeric and non-elastomeric components. The components include an elastomeric energizing component and a non-elastomeric seal ring configured to work together in attaining an internal seal sufficient for allowing the valve to remain consistently closed. Indeed, the aid afforded by the interfacing element may allow the valve to remain consistently and effectively closed even in particularly low pressure well environments or those of widely varying temperatures.
1 . A surface controlled subsurface safety valve assembly comprising:
a hydraulic line running from an oilfield surface;
a valve housing coupled to said line at a valve seat thereof; and
an interfacing element disposed in said housing for closing upon the seat and having an energizing component adjacent a non-elastomeric seal ring for meeting the seat upon the closing.
2 . The valve assembly of claim 1 wherein the seal ring is of a material selected from a group consisting of copper, brass and polytetrafluoroethylene.
3 . The valve assembly of claim 1 wherein the energizing component is selected from a group consisting of a spring and an elastomeric material.
4 . The valve assembly of claim 3 wherein the elastomeric material is selected from a group consisting of rubber and polyether ether ketone.
5 . The valve assembly of claim 1 further comprising:
a central channel disposed in said housing for guiding fluid from a location below the assembly to a location above the assembly; and
a valve disposed in said channel for regulating the guiding.
6 . The valve assembly of claim 5 wherein said valve is a flapper valve.
7 . The valve assembly of claim 5 wherein said interfacing element is disposed at an end of a hydraulic piston located in said line for coupling to said valve.
8 . The valve assembly of claim 7 wherein the coupling is provided by a responsive element disposed between said piston and said valve.
9 . The valve assembly of claim 8 wherein the responsive element is a spring for compressibly opening said valve in response to movement of said hydraulic piston in said line.
10 . A fluid control system for use at an oilfield, the system comprising:
well control equipment disposed at a surface of the oilfield;
a tubular disposed in a well at the oilfield and coupled to said equipment; and
a safety valve disposed in said tubular and having an element with energizing and non-elastomeric components for substantially maintaining a sealed interface at a seat of said valve during closure thereof.
11 . The system of claim 10 wherein said valve is rated to substantially maintain the closure at well pressure below about 50 PSI.
12 . The system of claim 10 wherein said valve is rated to substantially maintain the closure at well temperatures of between about 40° F. and about 350° F.
13 . The valve of claim 10 wherein said tubular is a production tubular.
14 . The valve of claim 13 wherein said equipment is a well head, said safety valve disposed subsurface within said production tubular adjacent said surface disposed well head.
15 . A method of regulating subsurface fluid flow in a well from a surface location adjacent the well, the method comprising:
closing a safety valve in the well to prevent fluid flow therethrough, said closing including allowing sealing of an internal piston of the valve at a valve seat of the valve; and
substantially maintaining said closing by way of an interfacing element of the piston having an energizing component adjacent a non-elastomeric seal ring, the ring to meet the seat for the sealing.
16 . The method of claim 15 further comprising directing an opening of the valve from the surface location prior to said closing.
17 . The method of claim 16 wherein said directing comprises maintaining hydraulic pressure on the piston throughout a duration of the opening.
18 . The method of claim 15 wherein the sealing is powered by a spring coupled to the piston and configured to responsively expand during the allowing.
19 . The method of claim 15 further comprising directing said closing from a control unit positioned at the surface location.
20 . The method of claim 15 wherein said closing is automatic in response to an emergent condition of equipment positioned at the surface location and in fluid communication with the safety valve.